The use of thermosetting resins or reactants to impart crease resistance and dimensional stability to textile materials is well-known in the art. These materials, known as "aminoplast resins", include the products of the reaction of formaldehyde with such compounds as urea, thiourea, ethylene urea, dihydroxyethylene urea, melamines or the like. A serious drawback to the use of such materials is that they contain free formaldehyde. This is present during the preparation and storage of the finishing agent and its use in treating textiles, on the treated fabric, and on the finished garments. Also, when the fabrics or garments made therefrom are stored under humid conditions, additional free formaldehyde is produced.
The presence of even less than one percent of free formaldehyde, based on the total weight of the product, is undesirable, not only because of its unpleasant odor, but because it is an allergen and an irritant, causing severe reactions in the operators who manufacture the agent and who treat and handle the treated fabrics and to persons who handle and wear garments fabricated from the treated fabrics.
These problems associated with the presence of free formaldehyde on treated fabrics are well-known and considerable efforts have been made to produce formaldehyde-free textile fabrics. One solution to the problem has been to employ scavengers for the free formaldehyde. In U.S. Pat. No. 3,590,100 cyclic ethylene urea and propylene urea are disclosed as scavengers. Removal of the formaldehyde by reaction with phthalimide is disclosed in U.S. Pat. No. 3,723,058. U.S. Pat. No. 4,127,382 teaches certain nitrogen-containing heterocyclic compounds as scavengers.
U.S. Pat. No. 5,858,549 describes compositions containing a poly-functional molecule having at least two functional groups selected from carboxyl, anhydride and amine which is crosslinked using a (hydroxyalkyl)urea crosslinking agent. U.S. Pat. No. 5,858,549 does not teach or suggest reacting a (hydroxyalkyl)urea crosslinking agent with textiles such as cotton which contain hydroxyl functionality. U.S. Pat. No. 4,076,917 describes .beta.-hydroxyalkylamides as curing agents for polymers containing one or more carboxy or anhydride functions.
Treating textiles with resin compositions that do not contain or evolve formaldehyde is also known, as in U.S. Pat. No. 3,260,565 which describes finishing agents formed by the reaction of alkyl or aryl ureas or thioureas with glyoxal. U.S. Pat. Nos. 4,332,586 and 4,300,898 describe alkylated glyoxal/cyclic urea condensates as crosslinking agents for textiles. U.S. Pat. No. 4,295,846 describes a finishing agent for textiles which is prepared by reacting urea or symmetrically disubstituted ureas in an aqueous solution with glyoxal. These agents, however, have the disadvantage of having marginal permanent press properties. Finishing agents formed by the reaction of ethylene urea with glyoxal are described in Japanese publication No. 5 3044-567, but they too do not have satisfactory properties. Thus, there is a need for a formaldehyde-free crosslinking agent which is environmentally safe and provides permanent press to textiles. Such crosslinking agents should also allow consumers the ability to provide permanent press properties easily and cost-effectively to clothing at home.